Practicality, in fact, a standardized test must be met, and it should not be too long because people are tired, heartburn and performed an error and also what yun need to stretch of the expense, and the right.
Practicality In fact, the tests must meet the standards. And there should not be too long. Because the symptoms of fatigue. And test errors And also take into account the flexibility of the test and the cost to some extent.